Mirror mechanisms of the type to which the subject invention generally relates are shown in U.S. Pat. Nos. 3,119,591 Malecki and 3,730,474 Bowers both of which are assigned to the assignee of the present invention. Mirror mounting mechanisms of the type to which the aforenoted patents as well as the subject invention relate have come to be termed "mirror swing lock mechanisms" which generally is intended to describe a mirror mounting mechanism wherein the mirror is normally positioned in a laterally extended position for normal rear viewing but which mechanism also permits the mirror support structure to be swung about a pivot axis to a position in which the mirror and mounting mechanism are generally flat against the side of the vehicle to prevent the former from being damaged. Such swing lock mechanisms also include detent devices which locate the mirror support arm in its normal laterally extended position for rearward viewing through the mirror.
In general, such swing lock mechanisms are used with larger mirrors of the type used on various types of trucks or heavy duty vehicles. Such truck mirrors are particularly susceptible to damage since they normally are mounted so as to extend laterally a considerable distance from the vehicle to permit adequate rear view sighting. Such truck mirrors are subject to being damaged by striking objects either during normal operation of the vehicle or when the vehicle is being itself transported. In either case, it is desirable that the mirror support mechanism fold back against the vehicle under conditions when it either strikes an object or to prevent it from otherwise being damaged during transportation of the vehicle itself.
Prior type mirror swing lock mechanisms have been less than completely satisfactory for several reasons. First, such mechanisms have been relatively complicated and have involved numerous parts which, in turn, have made such mechanisms difficult to assemble and, therefore, costly. Thus, it is applicants' first object to greatly simplify such a swing lock mechanism. Next, there have been relatively severe size constraints involved in designing such swing lock mechanisms and which constraints have limited spring sizes and, therefore, spring forces which may be utilized in holding the mirror arm in its laterally outwardly extended position in such a way as to prevent vibration and thereby assure a sharp image being viewed in the mirror. It is thus another object of the present invention to utilize a unique detent mechanism which enables the use of a spring having substantially greater mirror restraining force than has been possible in the past.
Such mirror swing lock mechanisms may not be utilized for long periods of time after being installed on a vehicle. Since such mechanisms have heretofore been entirely made of metal components, such components are subject to corrosion or rusting thereby inhibiting the protective actuation of such mechanism. Accordingly, it is a further objective of the present invention to incorporate a non-metallic spring element in the detent mechanism to eliminate such corrosion lock-up and further to provide an inherent lubricity and smoothness of action to the swing lock mechanism.